Name a personal-communications breakthrough in the past two decades, and chances are Wireless Zone co-owners Neil Ryan and Scott Gladstone have been all over it.

Today, it's the Isis Mobile Wallet, which allows Android users to make purchases through their cellphones rather than with a credit card. In the past, it's been car phones, pagers, personal digital assistants, tablets - you name it.

"This business is constantly changing and reinventing itself," Ryan said.

But through it all, say Ryan and Gladstone, has been one constant: customer service.

"People buy a new phone every couple years," Gladstone said. "We want to exceed their expectations and turn them into raving fans."

Among the ways Gladstone and Ryan make their customers happy at their stores in Groton and New London is by helping them set up their phones, downloading valuable apps and transferring data at no extra charge. Gladstone estimates that his staff spends about 45 minutes with every new smart phone customer, and says he offers ongoing support to help install new software.

"And it doesn't stop at the sale," Gladsone said. "We're here for them afterwards."

The local stores, for instance, offer free wireless-bill analysis to help customers determine how they could save money.

Gladstone and Ryan, college buddies from Keene State College, began their business together in December 1992 by installing car phones. A few months later they became the eighth franchisee in Russ Weldon's company initially known as the Car Phone Store, later the Wireless Zone, now a publicly owned company with more than 400 stores.

At first, most of their sales were to middle-aged business folks who could justify the high charges for car phones, which cost up to 50 cents a minute to use.

"The phone was not a social tool; it was a business tool," Ryan said.

Now, of course, everyone wants a cellphone, and the average age of a user comes down every year. Parents want kids to have phones for safety reasons, while teens want them to be cool.

And, as cellphones have evolved into smart phones, a range of other technologies have gone by the wayside.

"The cellphone killed the pager; it killed the camera, and the calculator," Gladstone said. "The cellphone is a device that people cannot live without."

And as the abilities of cellphones have evolved, Gladstone and Ryan's business plans have changed as well. With cellphones becoming more expensive, the pair moved aggressively in the past few months into repair services, offering a one-day turnaround.

"I'd rather be without my car than my phone," Gladstone said. "These days, you can't live without a phone for five days."

Gladstone said he expects repairs to be a significant part of his business this year, based on the first few months of booming sales. The repair business will more than make up for accessory sales that have declined over the past year as more cable connectors and the like have become standardized.

Gladstone and Ryan have 75 employees at 11 Wireless Zone locations, including their latest that opened in Hamden last October. All stores are in Connecticut, except for one in Brattleboro, Vt., near where Gladstone likes to ski.

Their stores are consistently in the top 10 nationally among all Wireless Zones, and the New London franchise was rated No. 2 in the country in 2012. Last June, Gladstone and Ryan were named original inductees in the Wireless Zone Hall of Fame.

"We are very liberal with our return and exchange policies," Gladstone said. "If there's a problem, we work as hard as we can to make it right."

Gladstone and Ryan also have earned plaudits in the community by consistently sponsoring a variety of events. Just last month, they earned the Greater Mystic Chamber of Commerce's Community Service Award, and Meagan Seacor, director of marketing and community relations for their Wireless Zone franchises, said she actively looks for worthwhile charitable causes and will sometimes call up an organization offering to make a donation.

Gladstone said his franchises also invest in their employees, offering constant training and hand-picking managers for new franchise territories. The managers make an investment and have part-ownership of their stores, he said.